The correct service and repair method for piston rings consists of standard procedures for evaluating all components including crankshaft and crankshaft bearings, camshaft and crankshaft bearings and cylinder head along with valve train (valves, seats, springs etc) and piston, piston pin, connecting rod and cylinder block and bore. The procedure for subassembly work includes servicing the cylinder head assembly followed by the piston assembly and the piston pin assembly and connecting rod assembly. Engine service and repair includes the steps required for both disassembly and assembly of the power unit. Not providing a dedicated service procedure for internal components suggests that manufacturers have omitted it but the service procedures needed appear in engine service and repair documents.